


My Poly Relationship Headcanons

by otomekaidii



Series: Obey Me Scenarios and Headcanons [4]
Category: Shall We Date?: Obey Me!
Genre: Bad Cooking, Baking, Ballroom Dancing, Barbatos knows everything, Brotherly Bonding, Brotherly Love, Chaos, Cooking Lessons, Cosplay, Cuddling & Snuggling, Domestic Fluff, Dorks in Love, Drunk Diavolo, Drunkenness, Established Relationship, F/M, Family Feels, Fluff, Gender-Neutral Pronouns, Gender-neutral Reader, Getting to Know Each Other, Gift Giving, Headcanon, Literal Sleeping Together, Love, Love Confessions, Lucifer plays Piano, M/M, Magical Accidents, Making Friends, Matching Jewelry, Mischief, Multi, Other, Other Additional Tags to Be Added, Overprotective, Partying, Piggyback Rides, Polyamorous Character, Polyamory, Polyamory Negotiations, Pranks and Practical Jokes, Protectiveness, Reader-Insert, Romantic Fluff, Secret Relationship, Slow Dancing, Sneaking Out, Tooth-Rotting Fluff, hand holding, headpats, so much chaos
Language: English
Status: In-Progress
Published: 2021-02-06
Updated: 2021-02-06
Packaged: 2021-03-18 16:48:44
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 4
Words: 3,094
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29246841
Author URL: https://archiveofourown.org/users/otomekaidii/pseuds/otomekaidii
Summary: A fun collection of imagined polyamorous relationships between various Obey Me characters.Some of these would be used in my writing, but most are just for fun. Feel free to use them as reference for your own stories, or inspiration to write your own headcanons!Lucifer x DiavoloMammon x LeviMammon x SolomonDiavolo x MammonNOTE - only the character names are mentioned in the chapter title. MC is involved in all the relationships.
Relationships: Diavolo (Shall We Date?: Obey Me!)/Reader, Diavolo/Lucifer (Shall We Date?: Obey Me!), Diavolo/Lucifer (Shall We Date?: Obey Me!)/Reader, Diavolo/Mammon (Shall We Date?: Obey Me!), Diavolo/Mammon (Shall We Date?: Obey Me!)/Reader, Leviathan (Shall We Date?: Obey Me!)/Reader, Leviathan/Mammon (Shall We Date?: Obey Me!)/Reader, Leviathan/Reader/Mammon (Shall We Date?: Obey Me!), Lucifer (Shall We Date?: Obey Me!)/Reader, Mammon & Solomon (Shall We Date?: Obey Me!), Mammon (Shall We Date?: Obey Me!)/Reader, Mammon/Solomon (Shall We Date?: Obey Me!)/Reader, Solomon (Shall We Date?: Obey Me!)/Reader
Series: Obey Me Scenarios and Headcanons [4]
Series URL: https://archiveofourown.org/series/2044858
Comments: 17
Kudos: 86





	1. Lucifer / Diavolo

**Author's Note:**

> Each relationship will involve MC and then 2 different characters. Only the character names are listed in the title for each chapter.
> 
> Mammon/Levi is xposted since it originally appeared as a separate post. I’m only adding it here for ease of reference.

**Summary for the Chapter:**

> Relationship headcanons for Lucifer x Diavolo x MC

  * When Lucifer confessed to you, the first thing he mentioned was that you’d need to be aware of his relationship with Diavolo.
  * You honestly laughed at him, because _of course_ you were aware. Was it supposed to be a secret?
  * (You had to reassure Lucifer that he doesn’t need to worry because everyone else is too scared to say anything.)
  * A relationship with these two is rather interesting.
  * Half the time is spent with you and Dia encouraging/forcing Lucifer to take better care of himself.
  * And the other half of the time is you and Dia causing mischief and giving Lucifer a headache.
  * Don’t be fooled though, Lucifer’s enjoying every minute of it. His pride just demands no one can know exactly how much he is.
  * Occasionally Lucifer likes to surprise you both by teaming up with Barbatos to “return the favor”. 
  * There exists at least one photo of Dia giving you a piggyback ride while he princess-carries Lucifer.
  * You’ll spend a lot of time bonding with Dia over your shared interest in Lucifer, such as swapping embarrassing stories and photos.
  * Lucifer pretends not to know about this.
  * Having alone time with you (and each other) is very important to both of them.
  * Especially in the early stages of your relationship with Dia because he’ll need the extra reassurance that you care for him too and aren’t intimidated by him. He just wants to know you genuinely enjoy spending time with him.
  * Barbatos is likely to be very suspicious of you in the beginning too, concerned about how much you actually care for Dia.
  * But he does eventually come around once you’ve demonstrated that you’re every bit as devoted to him as you are to Lucifer (even if it’s not in a romantic sense). 
  * Lucifer (and Barbatos) also appreciates the fact that with you around to keep Dia company when he is busy with his own work, Dia has an easier time focusing and getting things done.
  * Which leads to a happier Dia and a less stressed Lucifer. Win-win for everyone!
  * While Lucifer seems to prefer quiet, romantic dates, Dia is always looking for new adventures to share.
  * He also really likes taking the both of you on cliche dates simply because he’s never had the opportunity to do so before.
  * When it was just he and Lucifer, the two were often so busy with their own responsibilities that the only private time they had was spent at home instead of out in public.
  * Since you and Lucifer already have matching necklaces, you want to get Dia something special too - so you purchase a set of 3 rings. 
  * Lucifer wears his on the chain you’ve already given him, and you and Dia wear them on your fingers on opposite hands.
  * He loves it when he holds your hand and can feel the rings touching. And his mood always brightens when he catches sight of Lucifer’s chain and ring when he’s dressing.
  * Another favorite pastime is listening to classical music and Lucifer’s cursed records together.
  * Lucifer either plays the piano for you, while you and Dia dance, or the records are playing in the background while everyone takes turns dancing.
  * This only ever happens in the privacy of Diavolo’s castle though, because Lucifer would sooner die than let one of his brothers witness this. He knows they’d never let him live it down.
  * When cuddling together, Dia likes to be in the middle with yours and Lucifer’s heads on his chest.
  * But he’ll also be comfortable being on the outside since he’s big enough to hold you both at the same time, regardless of who is in the middle.
  * When you suggest to Lucifer that Dia be invited over more often for family activities, he’s resistant to the idea at first. He is certain his brothers are going to cause trouble and humiliate him. 
  * But as strict as the man is, he really can’t handle the power of double puppy dog eyes (you and Dia are a force to be reckoned with).
  * You help Dia fit in with the brothers and find things they can bond over to help the process go more smoothly. 
  * Dia has a blast getting to know the brothers better, and quickly befriends Mammon and Levi who just always seem to know the best ways to have fun.
  * And you might not know it, but Lucifer is watching all these interactions closely - his heart is just so full knowing that you’re helping bring them all together in a way he never thought possible.




	2. Mammon / Levi

**Summary for the Chapter:**

> Mammon x MC x Levi relationship headcanons

**Notes for the Chapter:**

> This set of headcanons was originally published as a separate post, and is just being added here for ease of reference.

  * Prepared to be spoiled.
  * You want to go somewhere? Tickets are already purchased.
  * You want to buy something? Oh what’s this, they just happened to have an extra.
  * After working out the kinks, they compliment each other well.
  * Just takes a bit for them to learn they don’t have to do *everything* on their own and that they can work together to keep you happy and feeling loved.
  * Mammon is great for outings and new experiences.
  * Levi is great for a night in or when you need quiet time.
  * Matching everything.
  * Expect Levi to make matching cosplay for everyone.
  * Mammon will complain, but he secretly loves it (and being included).
  * He eventually feels comfortable sharing suggestions of themes/characters with Levi.
  * Mammon looks out for Levi, reminding him how much you care for him when you aren’t there to do it yourself.
  * Levi still picks on Mammon, but isn’t as harsh.
  * It’s more of a friendly/teasing banter than an actual attempt to degrade.
  * They bond over things related to you.
  * Like swapping sexy stories like the perverts they are.
  * When Mammon is busy, he’s comforted knowing Levi is with you.
  * Despite all of Levi’s quirks, Mammon knows no one else could protect you as well (besides himself, of course).
  * These two get into so much mischief.
  * If something is broken/missing, or a random loud noise is suddenly heard - you can bet they are behind it.
  * Levi talks Mammon into a lot of shit just for the sake of DevilTube videos (let’s be honest, it doesn’t take much convincing).
  * Pretty sure they get dumber when they are together and unsupervised, scratch that. They definitely do.
  * Common sense? Never heard of ‘em.
  * Mammon is a closet geek.
  * Not as obsessed as Levi, but he has his fandoms, don’t be fooled.
  * They will bond over this too.
  * Would not be unusual for you to be totally clueless about something these two are obsessed with.
  * But you love watching them when they get like that.
  * Mammon stops stealing Levi’s shit, if only for the fact he probably helps him buy most of it now.
  * Levi buys extras whenever possible so Mammon can resell them (or keep them for himself because hello, closet geek).
  * If Levi is looking for a certain hard to find item, trust Mammon to be the one to find it.
  * Mammon tries to resell something to Levi at a markup a grand total of (1) times, but you’ll need to put a stop to that real fast.
  * They trade photos of you like Pokemon cards.
  * They think you don’t know, but of course you do.
  * Finally realize they aren’t as sly as they thought when you slip them a few new ones just because.
  * You must split their time up evenly between them.
  * Lots of planning, consider using a very fancy family scheduling app to make it all work.
  * If you are ok with it, you will never be alone again.
  * Otherwise better schedule chunks of “Me Time”.
  * Make sure to enforce boundaries because they will try to join in when it’s not their time, especially at the start when they are still adjusting to this idea of “sharing”.
  * Showing any sort of preferential treatment is sure to end very badly.
  * But if someone is having a rough time, exceptions can be made.
  * (Especially when it’s you who is sick/depressed)
  * They both deal with some of the same insecurities, so there’s a certain degree of understanding between them.
  * Just don’t ask them to talk about their feelings with each other.
  * They’ll only do that with you. Alone.
  * Prefer to spend time alone with you at first.
  * But after the relationship is more established, they enjoying hanging out as a group just as much.
  * They still need their private time with you though.
  * Both are very shy about showing you affection in front of the other, to start.
  * Mammon gets over this first, using it as a way to tease Levi and make him jealous.
  * Levi, jealous as he his, can’t let this stand so he works up the courage too.
  * Soon you are being lavished in affection & lots of cuddles.
  * Everyone is happy so long as they can touch and be touched by you.
  * Better like being sandwiched between these two while sleeping.
  * You’ll need to convince Levi to get a bed in his room so you and Mammon can spend the night while he does his thing.
  * And he can join you whenever he finally decides to rest w/o needing to leave his room. 




	3. Solomon / Mammon

**Summary for the Chapter:**

> Solomon x MC x Mammon relationship headcanons.

**Notes for the Chapter:**

> This has quickly become one of my new favorite relationships. Can you just imagine how much chaos and fun you could have??

  * When you first mention including Solomon in your relationship, Mammon is understandably jealous.
  * He’s a powerful sorcerer after all. And aside from his cooking problems, his résumé looks really impressive.
  * But as Mammon and Solomon get to know one another better (with your help), they realize they have more in common than they initially thought.
  * (so much chaotic energy, insecure, mischievous, trouble forming close relationships, lonely & touch starved etc)
  * After that, they become thick as thieves.
  * And then….oh lord help you.
  * The amount of chaos these two are capable of unleashing is not to be underestimated.
  * Poor Lucifer. The man may very well die from all the stress induced stomach ulcers they give him. 
  * Mammon comes up with the plots and the schemes like always. 
  * But now Solomon is on his team, and he has the power/knowledge/resources to make these things much more feasible than what Mammon was capable of on his own.
  * More than once they made decent Grimm by selling questionable magic potions that would later get banned for unintended side effects.
  * And just because Solomon is less impulsive than Mammon, doesn’t mean he’s capable of thinking things all the way through. Because he’s certainly not.
  * He only sees the immediate cause & effect, and often overlooks long term issues (ie. The unintended side effects of aforementioned potions).
  * But you love these two white haired idiots to pieces, and are very protective of them and all their eccentricities.
  * And they are extremely protective of you as well. 
  * Several times you’ve seen sketchy demons run away with their tails tucked between their legs when they see you with the two of them.
  * And there have also been a few instances where a random demon tried to hurt you when you were alone, and then just up and disappeared the next day. 👀
  * Expect lots of group dates doing normal human things.
  * Mammon enjoys them because he likes to imagine living that sort of simple life.
  * And Solomon likes the novelty of it; he’s never had these experiences before so it’s all new to him.
  * Also be prepared for a lot of surprises between the two of them (ie. gifts or activities).
  * One on one time is of course still very important to Mammon especially; just because he’s made a new friend doesn’t mean he’s going to be able to let go of centuries of insecurities just like that.
  * And Solomon appreciates quiet time with you too where he can just relax and have your undivided attention.
  * When it comes to snuggling together, you’ll always be in the middle.
  * They absolutely love to spoil you too. Lots of hand holding and hugs and stolen kisses.
  * Frankly, it makes the rest of the brothers rather sick to watch how sweet the three of you are together when they are doting on you, even if there isn’t a lot of physical affection involved. Just the dopey, love struck smiles y'all wear are enough.
  * You’ll need to do group cooking lessons with the two of them.
  * While Mammon might not have the same penchant for concocting dangerous substances while preparing meals, he’s not exactly a good cook either. So him working together in the kitchen with Solomon (alone) on anything is likely to go very badly.
  * Which is where you come in: teaching them the basics so at least when they feel like getting creative in the kitchen no one gets ill.
  * They both will get stupidly happy when you surprise them with baked goods of your own making. 
  * It’s best to provide separate treats for each, if possible, tailored to their own preferences. They both like that feeling of getting something “special” and just for them that they don’t have to share.
  * Mammon will start showing up for some of your sorcerer training sessions with Solomon.
  * He doesn’t participate at first, just sorta watches in the background and pretends not to be interested.
  * But after a while he wants to get involved too, and manages to convince Solomon to teach him some minor spells that are useful for making mischief.
  * Watching them practice magic together is honestly highly entertaining. 
  * Mammon is trying his best - partly out of his own personal interest, and partly to impress you. 
  * And Solomon is taking it all very seriously - partly because studying magic is the only thing he does take seriously, and partly to impress you.
  * On the plus side, you’ll get really good at healing magic and counterspells by the time all is said and done. 




	4. Diavolo / Mammon

**Summary for the Chapter:**

> A poly relationship with Dia x Mammon x MC.

**Notes for the Chapter:**

> NOTE - with this relationship, it’s implied that everyone involved has already made it known they are comfortable with a polyamorous and/or open relationship.

  * This seems like a really odd combination doesn’t it?
  * But after Mammon helped Dia sneak out so he can do “normal” and “fun” things, and avoid Lucifer and Barbatos (who stubbornly insist he needs to do work), the two started seeing more of each other.
  * And they bonded over this sense of mischief and love of fun.
  * You’re actually already in a relationship with Mammon when he finally tells you about how he and Diavolo have been seeing each other secretly for a while now (long before you arrived).
  * He was afraid to mention it to you because he didn’t know how you’d react. Would you want them to stop seeing each other? 
  * Or worse, would you not take their relationship seriously?
  * Mammon’s going to be having a breakdown over this, he hates feeling like he’s lied to you. And he’s scared.
  * You may be hurt at first that he didn’t trust you enough to tell you, but you do understand that he wasn’t exactly in an easy position either. This wasn’t something *anyone* could know.
  * You’ll need to obviously sit down with the both of them and make sure you are all on the same page.
  * And you may or may not have some choice words for Dia for putting Mammon in the position he was in.
  * It’ll take awhile for you to trust Dia. You can’t help it. You’re suspicious of him and his intentions with Mammon.
  * But after spending time together with the two of them, you quickly get to see how much he does genuinely care for him, and you warm up to him as well.
  * Poor Mammon doesn’t know how to handle this change. He’s just not prepared for the sheer amount of love and affection he’s going to be receiving now when you are all together.
  * And it’s really weird for him to be openly affectionate with Dia in front of anyone, even if it’s you, so that takes some getting used to.
  * You love to tease him about it though. He’s just so cute when he’s all blushy and embarrassed after all!
  * It also takes Mammon some time to get used to you being affectionate with him in front of Dia too.
  * But Dia loves to watch your interactions. He likes seeing Mammon look so happy. He knows how rough he has it sometimes with his brothers, and it’s a comfort knowing you can be there for him when he can’t.
  * When cuddling together, Mammon is almost always in the middle.
  * He’s still very much your protector when alone with you and out in public.
  * But something about being with you and Dia makes him...vulnerable. 
  * Probably because of how easy and natural the two of you make it seem to be protecting him. He can just _relax._ Because _of course_ you’re going to look after him and make sure he has nothing to worry about.
  * They both really enjoy headpats too, so another common position is you sitting upright, with Dia and Mammon each snuggling one of your thighs while you run your fingers through their hair.
  * With you involved, it does make it easier for Mammon to have reasonable excuses to stop by the castle. He’s your Guardian after all, isn’t he? So obviously it makes sense for him to accompany you when you join Diavolo for tea.
  * Dates tend to be either late night parties where Diavolo has managed to sneak away, or “stay at home” sort of dates where you and Mammon slip into the Castle.
  * But Dia’s dream is to take you both on a bunch of cliche, traditional dates out in the Devildom and the human world.
  * When sneaking out to parties, you’re surprised at how easily Dia blends in. 
  * He explains he uses certain spells and charms to make sure no one recognizes him, or that he at least doesn’t draw attention to himself.
  * These won’t work on people like Lucifer or Barbatos who know Dia well, only strangers and casual acquaintances.
  * When these two are determined to have fun, you’ll need to be the responsible one.
  * “Yes Dia, I know dancing until 3am is fun and you are drunk, but you have a meeting with Lucifer in less than 4 hours so you need.to.get.home.”
  * “No Mammon, you cannot spend the night in Diavolo’s bed because we have school in the morning.”
  * “Yes, I am sure Lucifer will notice if Dia tries to sneak into the House of Lamentation to spend the night and joins us for breakfast.”
  * It’s when you are bringing Dia home after one of these drunken excursions that you learn that Barbatos is indeed aware of Diavolo’s relationship with Mammon, and the mischief he gets up to, but he pretends not to notice and just keeps a watchful eye from a distance.
  * Eventually, after a lot of discussion between the three of you, Dia makes his relationships with you both public.
  * Lucifer almost dies of a coronary.



**Notes for the Chapter:**

> Loosely inspired by a fic I read on Tumblr that I absolutely cannot find. 😩 I’ll add the link here once I manage to track it down because I’m 99% sure I didn’t hallucinate it.
> 
> Found it! NSFW - 
> 
> https://diavolosthots.tumblr.com/post/641444445701668864/could-you-please-do-domdiasubmammon-nsfw
> 
> Read more about how the relationship between Mammon x Dia x MC develops - 
> 
> https://archiveofourown.org/works/27925696/chapters/71845119


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